Recent studies have shown that articulatory rehearsal prevents false memories in working memory tasks in young adults. During aging, a substantial increase in false memories has been documented in numerous studies. The aim of the present study was to investigate the role of rehearsal in the increase of false memories with age. In two experiments, we manipulated the opportunity to use rehearsal in a Brown-Peterson task in which younger (n = 80) and older (n = 70) adults maintained semantically related word lists and reported their maintenance strategies. Both experiments showed that reducing the opportunity to use rehearsal increased false memories and decreased correct recall in both groups. Furthermore, older adults made more false memories and less correct recall than younger adults, and these effects were partially mediated by the number of times participants reported using rehearsal (Exp. 2). These findings suggest that age-related differences in rehearsal use explain differences in working memory task performance.